Article date: 1990/7/1
PubMed ID: 2387285
Journal name: Epilepsy research (ISSN: 0920-1211)
A period of continuous hippocampal stimulation (CHS) establishes an acute condition of self-sustaining limbic status epilepticus (SSLSE) which is followed by chronic neuropathological changes reminiscent of hippocampal sclerosis encountered in epileptic patients. In the chronic (greater than or equal to 1 month) condition following CHS-induced SSLSE, extended electrographic monitoring in the hippocampus revealed spontaneous recurrent paroxysmal discharges. All 6 animals studied had persistent interictal spiking; 3 had multiple fully developed electrographic seizures. There was a marked diminution of paired pulse inhibition, demonstrated by a protocol known to reflect the potency of inhibition mediated by GABAA receptors. Hippocampal slices from animals that had previously experienced CHS-induced SSLSE demonstrated an increased excitability relative to slices from control animals as evidenced by epileptiform bursting in increased extracellular potassium ([K+]0) and decreased extracellular calcium ([Ca2+]0). These studies establish that CHS-induced SSLSE in rats provides an experimental model with recurrent spontaneous hippocampal seizures. Based on electrophysiological data we suggest that a decrease in GABA-mediated inhibition and/or altered sensitivity to extracellular ions may play roles in the development of such seizures.
Author List: Lothman E W, Bertram E H, Kapur J, Stringer J L
Publication Types: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.
Substances mentioned in the article: Muscimol;
Mesh terms: Action Potentials/physiology; Animals; Chronic Disease; Disease Models, Animal; Electric Stimulation; Electroencephalography; Electrophysiology; Epilepsy, Temporal Lobe/physiopathology; Hippocampus/physiopathology; Muscimol/pharmacology; Rats; Recurrence; Seizures/physiopathology; Status Epilepticus/physiopathology;